Badge not showing number after restarting Thunderbird

[aexvir]

Everytime I boot my Laptop the Thunderbird icon has no badge on it. Independently on the number of unread mails.

If i let Thunderbird open and I recieve 10 mails and I don't read them, the badge shows 10 unread mails. If I close Thunderbird and I reopen it, I still have those 10 mails unread, but no badge. Then, if I recieve an email, the badge shows 1 unread email, when, in fact, i have 11 unread emails.

I think the extension should in some way update the value when Thunderbird is open, in that way you can see if you left emails unread directly from the dock icon.